Edward f



E F. SMITH.

MANUFACTURE AND CONSTRUCTION m mmmmms.

APPLICATION FILED JULY 16x 19;.

2 V V 3 q J. Q hu mvu Aug 43, MIA

MT/YESSES [N i/EN 705'.

7% ykwg UNITED STATES PATENT OFFICE.

EDWARD F. SMITH, OF CINCINNATI, OHIO, ASSIGNOR TO THE NEIL & SMITHELECTRIC MANUFACTURE AND CONSTRUCTION OF COMMUTATORS.

Specification of Letters Patent.

Patented Aug. 22, 1916.

Application filed July 16, 1914. Serial No. 851,389.

To all whom. it may concern:

Be it known that I, EDWARD F. SMITH, residing at Cincinnati, Hamiltoncounty, State of Ohio, have invented certain new and useful Improvementsin the Manufacture and Construction of Commutators, of which thefollowing is a clear, full, and exact description, attention beingcalled to the drawing which accompanies this application and forms apart thereof.

This invention concerns the construction and manufacture of devicesknown as commutators and forming adjuncts of certain types of generatorsand dynamos. They consist of segments assembled side by side andradially disposed around a common center so as to form a. cylindricalbody which is adapted to be mounted upon a shaft, each segment beinginsulated from the other and from said shaft. A so-called brush, anotheradjunct, is used in connection with these commutators, it being held inyieldingcontact with the outer, cylindrical side thereof and while oneof these devices rotates with reference to the other one. It isdesirable that this contact be a perfect one and .without the slightestinterruption, otherwise sparking results which is very objectionablebecause destructive to the commutator and to the brushes. Suchinterruptions result when the surface of the commutator which is incontact with the brushes is not cylindrically true, if insulatingmaterial and segments do not wear-away equally, leaving ridges, or ifthe segments with the insulating material between them are not so firmlyheld together as to form an absolutely rigid body. Either one of theseconditions produces vibrations of the brushes whereby terfiporarilytheir contact is interrupted, causing the gap to be bridged by theobjectionable spark.

The object of my invention is to construct commutators in a mannerwhereby the various segments are firmly held together so as to form withthe insulating material between them a solid mass, homogeneous andintegral for all practical purposes and to present a brush-contactsurface which wears equally in all its parts and remains thereforecylindrical at all times.

The invention consists of the method of producing commutators in themanner aforesaid and of the commutator itself and constructed inaccordance with this method.

In the following specification and claims is found a full description ofmy invention, its parts, and the manner in which it is practised, all ofwhich is illustrated in the accompanying drawing in which:

Figure 1 shows in perspective view a block of metal to be used in theproduction of a commutator according to my plan. Fig. 2 shows acommutator blank formed out of this block. Fig. 3- is a vertical crosssection on a planeindicated by numerals shown in Fig. 2. Fig. 4 in asectional view shows an apparatus whereby the aforesaid blank is actedupon in a certain manner. Fig. 5 in a view similar to Fig. 2, showsappearance of the blank after having been acted upon by the apparatusshown in Fig. 4. Fig. 6 also a similar view, shows the blank furtheradvanced in the state of its manufacture. Fig. 7 is an axial section ofthe completed commutator.

In the drawing, Fig. 1, shows suitable metal preferably'copper which isused in my improved manufacture of commutators and in a preliminaryshape which may be the form of a cylindrical block 10. This block, bysuitable machine "001 operation, is further shaped so as to have acentral bore 11, countersunk recesses 12, 12 in its opposite flat sidesand radially arranged cuts 13 which extend in from the peripheral sidetoward said bore. These cuts are all of practically equal depth andterminate so as to leave an intact annular zone of metal 14 around saidbore so that a blank results as shown in Figs. 2 and 3. This blank isnow placed within a cylinder 15 and with one of its flat sides upon abase 16 as shown in Fig. 4. Dielectric material 17, in plasticcondition, is placed upon the blank within the cylinder and by means ofa plunger 18 this material is forced against said blank so as to enterall open parts of the same, particularly cuts 13, the object being tofill these latter completely. Material in excess of that really requiredis used and cylinder 15 rests loosely upon base 16, so'that the surplusmay disgorge from below the lower edge of the cylinder, this latterbeing lifted by the reaction. This impressing of material may berepeated until all of the cuts 13 and each one of them are thoroughlyfilled and packed. The blanks are now removed from cylinder 15, surplusmaterial, especially that which fills bore 11 and recesses 12-42, isremoved and they are set aside to permit the material to harden. Thismay be effected byair-drying, if there is sufiicient time; otherwisehtheuse of artificial heat will be resorted to. Next the blanks whilesecured in a suitable holding device are rebored torem ove themetal ltwithin I bore 11 from which actionfinally a struc- .and consisting oftwo complementary mem- 'bers 21 and22,"is finally placed into bore '11and recesses 12-12. It. is insulated from the commutator by washers 23."Material 17 in addition to beingdielectric should be also inert andneutral with referenceto the acv tion of acidsor alkalis and so as'not'to he ture results as'shown inF-igsgfi; and 7, and composed of; segments19, 'allfin'sulated from each other by material'l? whereby they are alsoheld together. A usual bushing, to form a bearing for the commutatorsusceptible to the action of grease, oil or water, nor aflected by heat.Pulverized as-Q bestos or mica mixed with"a suitable binder arepreferable materials. I use pulverized -mica formed into a plastic massby means of silicatemf soda. Whiting is added to overcome the porosityofthe micawhich would reduce the densityof the massand render it more orless elastic. This mass by being applied in the manner statedautomatically fills cuts 13 completely, no matter whether they areperfect or not, that is ness, they cannot adjust themselves toirre'gularities in the shape of the segments or in the surface of thesides thereof, nor to differences in the size of the spaces'betweenthem. As a result neither the segments nor the material between them areheld rigid, spaces result between them, they do not form a compact body,segments may move and possibility of vibration exists. Furthermore, 1napplicants case, the material is of a granular texture, and wears away.even with the tree outer ends of the seg-- ments so that no high spotsor ridges re- The apparatus for applying the insulating material may beof a size to admit a number of blanks,- superposed, or side by side, sothat a number of them may be acted upon. Byproperly gaging the quantityof the mass, the operation'may consist of one operation of the plungeror-several charges may beappliedt I Having descri asnew: .r 1. Themethod of manufacturing commutators which consists of producing anintegral cylindrical blank of metal which con tains the metal forthesegments and is provided with radially disposed spaces between the metalintended 'for said segments, of

filling these spaces with insulating material and of removing the metalat the inner ends of these filled spacesso as to completely separate thesegments from each other;

'2. The method of manufacturing commutators which consists of producingan in,

tegralcylindrical blank of metal which contains the metal for thesegments and is provided with radially disposed spaces between the metalintended forsaid segments, of filling these spaces with insulatingmaterial and of axially boring out said blank, the

bore being of an extent to reach into the in- 86 ner ends of the filledspaces so as to completely part the segments from each other. Intestimony whereof, I'hereunto atfix my signature in the EDWARD F. SMITH.

Witnesses: i

C. s asm, A. JOHNSON.

bed invention, I claim 65 presence of two witnesses.

